The former Dundee United star has struggled for first-team opportunities with the Lisbon giants since his 2014 move.
Last season he spent time on loan with Vitoria Setubal, though the deal was cut short when the Primeria Liga side dumped Gauld’s parent club out of the cup.
Desportivo Aves achieved promotion to the top flight last season after finishing second in Liga Pro.
Clubs back in Scotland had been monitoring Gauld’s situation. The player has said in the past he’d prefer to secure a loan move on the continent to gain first-team experience rather than return home.